1. Field of the Invention
The present invention relates to a circuit for driving a plasma cell used in a display device or the like, and more particularly to a plasma driving circuit for sequentially discharging and driving a plurality of plasma channels provided in a plasma cell. And further particularly the invention relates to a technique of suppressing a rush current (surge) derived from an internal capacity of a plasma driving circuit.
2. Description of Related Art
It has been known heretofore that a plasma cell having a plurality of plasma channels is employed in a plasma display device (PDP). Relative to a plasma addressed liquid crystal display device (PALC) where a plasma cell is utilized for addressing a display cell, exemplary ones are disclosed in U.S. Pat. No. 4,896,149 to Buzak (Issue date: Jan. 23, 1990) and U.S. Pat. No. 5,077,553 to Buzak (Issue date: Dec. 31, 1991). In such display devices, each of the plasma channels is equipped with an anode and a cathode as a pair of discharge electrodes. The plasma driving circuit connected to the plasma cell sequentially supplies a discharge voltage between the anodes and the cathodes of the individual plasma channels to thereby generate plasma discharges. In utilizing a plasma cell for a PDP or a PALC, it is necessary to generate stable plasma discharges in the individual plasma channels without any secular change that may be caused with a lapse of time.
However, in generation of a plasma discharge, there may occur a case where an unintended and unrequired current (rush current) flows from a plasma driving circuit. Such a rush current results from the internal capacity of the plasma driving circuit and, since it is difficult to control the flow thereof, the rush current renders the plasma discharge unstable. Generally, the service life of a plasma cell consisting of a structure with a set of plasma channels is in inverse proportion to the square or cube of discharge current, whereby there is raised a problem that the service life is shortened correspondingly to the addition of rush current.